(1) Field of the Invention
The present invention relates to a surface grinding apparatus. More particularly, the present invention relates to a surface grinding apparatus for grinding uniformly and efficiently surfaces of various materials having a flat surface and differing in shape, such as plate-like and disk-like materials composed of metals, glass, synthetic resins, or the like.
(2) Description of the Related Art
Surface grinding of metal plates, glass, sheets, synthetic resin plates, and the like is often performed by a lapping machine. Such a machine is provided with a plate-like lapping platen or a lapping platen having artificial suede leather bonded thereto. A material to be ground is pressed to the lapping platen, grinding slurry containing abrasive grains is steadily supplied, and the material is slid on the lapping platen. Various lapping machines are known for performing such grinding operations, for example, a lapping machine is which a single lapping platen is rotated to effect grinding at a high efficiency and a lapping machine in which a material to be ground is gripped between upper and lower lapping platens rotated in opposite directions to simultaneously grind both surfaces of the material.
In each of these known machines, grinding is carried out with a steady supply of a slurry containing a high concentration of abrasive grains to the surface of the material to be ground. The abrasive grains contaminate the apparatus and equipment. Furthermore, the amount of abrasive grains effectively used for the grinding is very small, though a large quantity of abrasive grains is used overall. This increases the grinding cost. Moreover, the waste liquid containing the abrasive grains and grinding shavings must be treated before discharge.
As means for overcoming these defects, it has been proposed to mount a solid grinding wheel having abrasive grains incorporated therein on a lapping platen and perform grinding with a steady supply of water or water containing a small amount of a surface active agent instead of the abrasive grain-containing slurry. This method, however, is defective in that abrasive grains falling from the grinding wheel and grinding shavings intrude into fine pores on the surface of the grinding wheel, causing loading and necessitating frequent dressing operations to prevent reduction of the grinding power.